1. Field of the Invention
The invention relates generally to digital image processing and, more specifically, to a digital image processing system and method for enhancing the edge characteristics of printed or displayed images that are generated from low resolution image files, which include binary image data or a mixture of binary and gray-scale image data.
2. Description Relative to the Prior Art
Edge or line jaggedness is a common problem associated with the printing of low resolution binary image data. Efforts have been made to reduce or overcome line jaggedness. In this regard, reference is made to U.S. Pat. No. 6,021,256, wherein there is disclosed a system for performing edge enhancement of mixed binary and gray level image files which employs a binarization and sorting unit to sort data that is indicative of binary data from the mixed binary and gray level image input file. The sorted binary data is then supplied to a binary data edge enhancement processor for edge enhancement processing. The output from the binary data edge enhancement processor unit is supplied to a data merger unit along with the original image data. The data merger unit determines whether the original image data was part of a gray scale image. If the data merger unit determines that the original data is binary image data, the output from the binary edge enhancement processor unit is supplied as the output of the processing system. While the system described in this patent works well, a problem may arise wherein the image data represents color separation image data that has previously been subjected to under color removal and/or gray component replacement and/or a color transformation process wherein the resulting image data has gray scale values that fall short from that expected by an edge enhancement processor that is adapted to operate on binary image data. The edge enhancement processor thereupon considers all the image data to be gray level image data and selects such image data for output whereas at least a portion of this image data may represent binary image data that is more preferably selected after edge enhancement processing than the image data entering the edge enhancement processor.
The above and other needs and objectives are accomplished in accordance with the invention described herein.